Tampa Bay Water officials have figured out what's causing all the cracks in the state's largest reservoir — and fixing it will require raising rates for the region's 2 million water customers, general manager Gerald Seeber said Thursday.
There's more bad news. During the repairs, scheduled to begin in June 2012, the reservoir will have to be drained dry for two years.
"In order to do the kind of work that needs to be done here, the reservoir needs to be empty," Seeber said during a meeting with the Times editorial board.
The only silver lining: Tampa Bay Water is suing the companies that built the 15-billion-gallon reservoir in the hopes of recouping at least some of the repair cost. If that happens, there could be a rebate to customers, Seeber said.
At this point, Seeber said, no one can say for sure how much it will cost to fix the cracking problem, but one early estimate puts it in the neighborhood of $125 million — nearly as much as the $146 million facility cost to build. Until the utility can figure out the full cost of the repair, no one knows how much rates will have to be increased.
Whether keeping the reservoir empty for two years will require imposing watering restrictions depends on the weather and the capability of the utility's other water-producing resources, he said. Because the repairs won't begin until 2012, that gives the utility time to boost the capacity of its surface-water treatment plant to 120 million gallons a day.
The utility opened the C.W. Bill Young Regional Reservoir in June 2005 as a place to store water skimmed from the Alafia River, Hillsborough River and Tampa Bypass Canal. The reservoir, named for the longtime congressman from Pinellas County, is the largest in Florida, covering about 1,100 acres.
The reservoir's walls consist of an earthen embankment as wide as a football field at its base, averaging about 50 feet high. An impermeable membrane buried in the embankment prevents leaks.
The embankment's top layer is a mixture of soil and cement to prevent erosion. That's what cracked in December 2006. Some cracks were up to 400 feet long and up to 15½ inches deep. Workers patched the cracks, but the fix didn't last.
Although some initial news coverage questioned whether the reservoir's walls would fail, Seeber said Thursday that "the facility is safe. ... The membrane has not been compromised, and that's what holds the water in."
An investigation found water is getting trapped between the soil-cement lining and the membrane, utility officials said. As long as the reservoir is full, the trapped water remains stable. When the utility draws down the reservoir, though, pressure increases on trapped water in some areas, producing cracks and soil erosion. The reservoir is now down to 1.7 billion gallons.
The utility's board voted last fall to sue HDR Engineering, which designed the reservoir; Barnard Construction Co., which built it; and Construction Dynamics Group, which oversaw the construction. The board also fired HDR from its job of filing monitoring reports on the reservoir. The federal case is set for trial in 2011.
According to Seeber, the problem originated with a last-minute design change. The state Department of Environmental Protection, while reviewing the reservoir's permit application, had suggested adding another layer of soil to protect the membrane from tearing, he said.
So that's when HDR Engineering added a soil wedge between the soil-cement layer and the membrane — but the company did not take into account the possibility that water could get trapped beneath it, the general manager said.
"We believe they failed us in that regard," Seeber said. "They should've come up with something that worked, a drain facility of some type. You can't build a facility like this without providing a way for water to get out."
HDR spokeswoman Jackie Fox said: "HDR is fully cooperating with Tampa Bay Water to find a resolution that is agreeable to all parties.'' She declined further comment since the case is in litigation.
Fixing the problem will probably require removing the soil layer and installing drains throughout the walls, which are 5 miles around. Seeber said that before construction begins, any repair solution will undergo a lengthy peer review by experts — another reason why construction won't start until 2012.
While investigating the cause of the cracks last fall, utility officials drained off half the water in the reservoir. But the winter turned out to be drier than expected, and by March the utility had used up virtually the last drop, leaving only its well fields and desalination plant to slake the region's thirst.
The shortage prompted the Southwest Florida Water Management District to impose the toughest watering restrictions in history on Pinellas, Pasco and Hillsborough counties. The utility also faces a possible fine for pumping too much water out of the underground aquifer — something the desal plant and reservoir were supposed to stop.
In the 1990s, when groundwater pumping drained swamps and dried up private wells, Swiftmud helped form Tampa Bay Water and agreed to help develop alternative water sources. With tax money from Swiftmud, the utility then built its reservoir, the 25-million-gallon-a-day desalination plant — the largest in the nation — and a 66-million-gallon-a-day surface water treatment plant.
The reservoir is not the only facility to run into problems. The surface-water treatment plant opened four months late and its filters repeatedly clogged. The desalination plant wound up being five years late and $40 million over budget when it finally opened last year.
Tampa Bay Water's governing board is scheduled to discuss the reservoir and its repair at its next meeting June 15 in Clearwater.
Craig Pittman can be reached at (727) 893-8530 or firstname.lastname@example.org.